Householders are being warned to be on alert for cold callers claiming to be police officers across Norfolk.

Police have received reports of five cases within the past week where an elderly person has been called by someone claiming to be an officer.

The first incident happened at Ashill, near Watton, on November 27. There have since been similar calls to people in Thetford, Diss and Holt.

The fraudsters claim that someone the victim knows has been arrested before asking for personal bank details.

Detective Inspector Bruce Clark said: “We are concerned about the number of reports we have received in the past week about this scam and we’re urging members of the public, particularly the elderly who are primarily being targeted, to be vigilant to cold calls made on the telephone.

“In some of these cases the victim has handed over a large quantity of money, whilst in others the victim has become suspicious and ended the call.”

Genuine police officers or staff never approach residents and ask for cash withdrawals to be made or for people to purchase items on their behalf, he added.

People are being advised that if someone calls claiming to be a police officer, ask for their identification number and police force. Hang up and call 101 using a different phone. If you can’t use a different phone, wait at least five minutes before calling back. Police will not mind waiting while you check.

Never give out personal information about your bank account to anybody over the phone. Neither police nor banks will ever ask for personal details such as account numbers or PIN numbers.

If you have given out information which could compromise your bank account security in any way, call your bank to cancel your cards as soon as possible.

Det Insp Clark said: “I would ask people with vulnerable relatives, friends or neighbours to make sure they are aware of this type of scam.”

Anyone with concerns about cold calls should contact Norfolk Constabulary on the non-emergency number 101 or 999 if a crime is in progress. Alternatively, contact Action Fraud on 0300 1232040.